Fire link and method of actuating same

ABSTRACT

A releasable link is provided to open under predetermined conditions; said link having the capacity to be reset under predetermined temperature conditions. The link includes a bimetallic element for effecting opening and closing. The link may also include heating means for actuating the bimetallic element, and secondary circuit control means for actuating signals or controlling current to the heating means.

United States Patent 1191 McCabe [451 Apr. 10, 1973 [54] FIRE LINK ANDMETHOD OF 1,471,537 10 1923 Wills et a1 24 230 F UX ACTUATING SAME2,253,861 8 1941 McKune et a1. ..16/48.5

, 2,573,160 10/1951 Norman ..49 1

[76] Inventor: Francis J. McCabe, Hollow Horn 3,273,632 9/1966 Mccabe u160/1 Road & Cafferty Hill Road, Erwin- 3,584,763 6/1971 Donselman...49/1

na, Pa. 18902 587,823 8/1897 Holbrook et al. ...49/1

. 599,800 3 1898 Scribner 4 ..49 2

[22] Wed Sept 1971 3,249,148 5/1966 Zablodil et a1. ..160/5 x 2 N 178111 3,415,562 12/1968 Petersen 1 ..l6/48.5 X 3,648,326 3/1972 Gaysowski..l6/48.5

Related US. Application Data Continuation-impart of Ser. No, 103,467,Jan. 4, 1971, abandoned, and a continuation-in-part of Ser. No. 133,196,April 12, 1971, abandoned.

US. Cl ..16/48.5, 49/2 Int. Cl. ..E05f 15/20 Field of Search ..l60/l, 2,6, 8, 5;

References Cited UNITED STATES PATENTS Simpson ..24/230 F UX I Shuman160/1 Primary Examiner-Donald A. Griffin Attorney-frank J. Benasutti[57] ABSTRACT A releasable link is provided to open under predeterminedconditions; said'link having the capacity to be reset underpredetermined temperature conditions. The link includes a bimetallicelement for effecting opening and closing. The link may also includeheating means for actuating the bimetallic element, and

secondary circuit control means for actuating signals or controllingcurrent to the heating means.

18 Claims, 5 Drawing Figures PATENTEBAPR 1 D I913 SHEET 1 [IF 3'PATENIEDAPM oma 3725972 'SHEET 3 or 3 24 ZIO 284 280 2 1 FIRE LINK ANDMETHOD OF ACTUATING SAME CROSS-REFERENCE TO RELATED APPLICATIONS133,196, filed Apr. 12, 1971, and discloses and claims,

in part, the subject matter disclosed and claimed in those applications.

BACKGROUND OF THE INVENTION This invention related to links for use inautomatically actuated equipment forming a part of a tirefightingsystem, and more particularly, to a fire link for use with devices suchas fire dampers in air ducts.

In the prior art, such links were generally made of two pieces of metalfused together with solder; the solder being the means for releasing thelink when the ambient temperature rose above a certain level; forexample, 160 F. Such links are shown in use with fire dampers in myprior U.S. Pat. Nos. 3,273,632 and 3,401,734. It will be observed inthese patents that the melting or change of state of the solder permitsthe link to be opened by the fire damper to close off the air duct.

It is also known to provide a means for melting the solder by remotecontrol.

In practice it is difficult to make these links accurately, since it isparticularly difficult to control the amount of solder and the solderdistribution on the links. Further, as a practical matter the links arenot 'resettable.

It is desirable to provide a link which is capable of being manufacturedso that it opens or releases at a predetermined temperature. It isfurther desirable to have such a link which can be reset and which canbe remotely operated.

SUMMARY OF THE INVENTION My invention provides a mechanically operableresettable link capable of highly accurate predetermined control as toopening and closing; which does not undergo a change of state in orderto function. The link also provides a means whereby remote control canbe used to actuate the link. The link comprises two parts interconnectedby a pin. When the pin is withdrawn, the parts can be separated. A meansis provided for withdrawing the pin; said means being a bimetallicelement upon which the pin is mounted.

Further means are provided in alternate embodiments of the invention forheating the bimetallic element by remote means and for automaticallysignalling and controlling the heat to the element.

Accordingly, it is an object of my invention to provide a new and novelfire link which can be simply and accurately manufactured.

Another object of my invention is to provide such a link which does notundergo a change of state and which can be reset.

A further object is to provide such a link which can be remotelycontrolled.

A further object is to provide a link with means to control secondarycircuitry for signalling or controlling the action of the link.

These and other objects of my invention will become apparent from thefollowing description with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a tirelink in accordance with one embodiment of the present invention;

FIG. 2 is a top view of the link shown in FIG. 1;

FIG. 3 is a view taken as indicated by the lines and arrows e-3 in FIG.2;

FIG. 4 is a view of another embodiment of my invention, similar to FIG.3; and

FIG. 5 is a view of another embodiment of my invention, similar to FIG.3 with the parts reoriented.

The figures include positive and negative signs to indicate electricalpotential.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although specific forms of theinvention have been selected for illustration in the drawings, and thefollowing description is drawn in specific terms for the purpose ofdescribing-these forms of the invention, this description is notintended to limit the scope of the invention which is defined in theappended claims.

- In FIG. 1 a link is shown in accordance with one em bodiment of thepresent invention wherein a remote control device is utilized with thelink to accuate the link and openit. This remote control devicecomprises an electrically operated heating element. To understand thenature of this heating element and its function with the basic linkconstruction in accordance with the preferred embodiment of the presentinvention, I will first describe the link and its function without theuse of this electrical heating element.

The basic link comprises two elements which are pin connected together.The first link element 10 is a substantially flat, rectangular metalstrip having joined thereto in any suitable manner a number of othermetal strips and including at one end a hole 12 providing a ready meansfor attachment to a wire or chain in a tire damper or the like.

The second link element 14 is also a substantially rectangular flatmetal strip with a hole 16 at one end also providing a means for readyattachment to a wire or chain in a fire damper or the like. The elementsare normally held together by pin 18 which passes through a clearancehole 20 in element 10 and a clearance hole 22 in element 14.

A flange 24 is provided on the element 10. The flange is made of a flatstrip of metal which has been bent intermediate the ends thereof so thatwhen one portion is held flat against the underside of element 10 and iswelded thereto, the remainder extends outwardly away from and thenparallel to the element 10. Thus, there is formed an envelope orenclosure confining the element 14; both while the pin 18 is in theposition shown in FIG. 3, and while it is being withdrawn.

The pin 18 passes through the clearance hole 26 in element 24. The pinis connected by means of a swaged rivet 28 to'a bimetallic element 30.The bimetallic element is made of two flat strips of dissimilar metalsadhered together in any well known manner. Bimetallic elements arecommonly used in thermostats and the like. The strips of metal formingthe bimetallic element 30 are attached at one end to the element as bymeans of the rivets 32. The bimetallic element is similar in form to theelement 24 so that it extends outwardly from the point of engagement at32 to a point clearing the element 24, at which point it extendsparallel to the element 10.

What has been described thus far is the basic link in accordance withthis invention, although it will be apparent from this disclosure thatchanges could be made within the principle of the invention. Inoperation the bimetallic element is arranged so that in normal ambienttemperatures it is in the position shown in FIG. 3 with respect to theelement 10 and the element 14. In this position the link is connected orclosed, and if the ends of the members 10 and 14 were connected to awire or a chain in a fire damper the forces on the link would be in thedirection of the arrows shown in FIG. 3.

The link would be in position to retain the blades of the the metals inthe bimetallic element would cause its free end 34 to move away from thefree end 36 of the element 10. As it did so, it would withdraw the pin18 from the hole 20 and hole 22 and as the pin was completely withdrawnfrom the hole 22 the elements 10 and 14 would separate from one anotherunder the action of the forces from, say, the weight of the damperblades.

Note that the action of the link is purely mechanical and it does notundergo any change of state. Therefore, in the event that the link isnot damaged in whatever fire caused the temperature to rise, the linkcan be reset at normal temperatures. The bimetallic element returns tothe position shown in FIG. 3 at normal temperatures.

The large oval hole 38 in the element 10 provides a means for allowingthe heated air to flow through and come into contact with bimetallicelement 30, thereby increasing the efficiency of the device.

In an alternate embodiment of this invention, a means is provided forremotely controlling the action of the bimetallic element. This meanscomprises an electrical heating element which, in its preferredembodiment, comprises nichrome wire 40, which is adhered by any suitablemeans, such as adhesive to the inner surface of the bimetallic element30. The positive and negative electrical leads indicated on the drawingsprovide a means to establish current flow through the nichrome wire fromany suitable controlled electrical source (not shown) to heat the wireand the bimetallic element. Thus, it is possible to energize thenichrome wire and provide heat to the link to open it in the mannerpreviously described and allow the tire damper, or whatever device wasbeing controlled by the link, to become operative. It will be understoodthat various changes in the details, materials, and arrangements ofparts which have been herein described and illustrated in order toexplain the nature of this invention, may be made by those skilled inthe art within the principle and scope of the invention as expressed inthe claims. For example, a portion of the bimetallic element itself canbe the heating means.

In the embodiment shown in FIG. 4, the electrical leads are directlyconnected to the bimetallic element 130. Since the element will carrycurrent, it is insulated at its point of connection to element 110 aswell as at the pin 118. This electrical insulation is provided bywashers 150, 151, 152 and 153, and by bushings 154 and 155. In thismanner, the bimetallic element 130 can be heated directly from a remotesource to open the link.

Alternatively, in either of the electrically operated embodiments, themetals in the bimetallic element can be reversed so that it must beconstantly heated in order to remain closed. If the circuit is openedand the electrical power cut off, then the link would openautomatically.

Mechanical details can also be changed within the scope of thisinvention, such as by providing a hook 112 at the end of the element 110in lieu of the hole 12 FIG. 1 and/or a double ended hook 116 in lieu ofthe element 14, FIG. 1.

In FIG. 5 a further embodiment of my invention is shown in an opencondition, that is, wherein the bimetallic element has withdrawn the pinfrom the envelope created by the flange 24 and the main body 210 of oneelement of the link thereby allowing the other element of the link to beseparated by the opposed forces (shown by arrows in FIG. 3). Thisembodiment is provided with means for controlling a secondary cir-- cuitfor purposes of signaling in the event that the link is opened or forpurposes of controlling the amount of heat supplied to the bimetallicelement in order to prevent it from overheating and being destroyed.This secondary circuit control means comprises two substantially flatnarrow gage flexible metallic elements which are normally bent so thatthey are in contact when the device is in the closed position with thepin 218 fully inserted through the holes in the hole member 210. Theelements 280 and 282 each have a small metallic button 284,286respectively riveted to the adjacent free ends thereof. The other endsare retained as follows. The end of the element 280 is held inelectrical contact with the electrical take off lug 288 which isinsulated from the main body 210 by the insulator pad 290. On the otherside of the element 280 there is a further insulator pad 291 whichinsulates these elements from the bimetallic element 230. An electricallug 292 is in electrical contact with the bimetallic element 230 and aninsulator pad 293 separates this lug from a metallic retainer pad 294.All of these pads and parts are held together by a plurality of rivets,such as the rivet 295, which pass through clearance holes in theelectrical elements and are rolled over to retain the elements in a firmfixed position. The pin 218 is electrically insulated by a washer 219from element 282 which is in electrical contact with the bimetallicelement 230. A further insulator washer 221 is provided between theretainer washer 223 and the rolled head of the pin 218 so that theseparts are likewise held in a firm fixed position and are electricallyinsulated as shown.

When the bimetallic element is heated and is moving from a fullyclosedposition to the position shown in FIG. 5, the buttons 284, 286will remain in contact for a predetermined distance. In the event thatit is desired to signal the opening of the link, the elements 280, 232

can be bent before hand to an extent necessary such that when the pinmoves to the position shown in FIG. 5 the buttons will separate as shownand break a circuit. A circuit, such as a low voltage secondary signalcircuit can easily be provided from the lugs 288, 292 and secondaryinstrumentation or signal controls can be actuated by merely brakingthis circuit. These are not shown in further detail, since such circuitsare well known.

Alternatively, if it is desired to heat the bimetallic element 230through circuitry connected to these lugs, the separation of the buttonsat a predetermined point will prevent overheating by breaking thecircuit. However, the link will be maintained in the opened position aslong as the circuit remains closed and as the bimetallic element 230cools the buttons 284, 286 will come together and close the circuitagain thereby reheating the link.

It will further be understood that the Abstract of the Disclosure setforth above is intended to provide a non-legal technical statement ofthe contents of the disclosure in compliance with the Rules of Practiceof the U.S. Patent Office, and is not intended to limit the scope of theinvention described and claimed herein.

Iclaim:

1. A releasable link having only two elements comprising: a firstelement; and a separate heat activated bimetallic second elementnot'fixedly connected to, but directly engaged with said first elementand coacting therewith to allow said elements to separate in response totemperature change without changing the state of either element.

2. The invention of claim 1 wherein a remotely controlled heating meansis connected to said bimetallic element for actuating said bimetallicelement.

3. The invention of claim 2 wherein said heating means comprises anelectric heating element engaging said bimetallic element.

4. The invention of claim 1 wherein a pin is attached to said bimetallicelement and passes through said first element.

5. The invention of claim 4 wherein said bimetallic element is fixedlyconnected to a base at one end and said pin is connected to the free endthereof.

6. The invention of claim 4 wherein said second element includes a meansembracing said first element to confine it. I v

7. The invention of claim 1 wherein said second element is provided withmeans to provide an air passage to the bimetal.

8. The invention of claim 1 wherein said electrical means are connectedto said bimetallic element for heating said element.

9. The invention of claim 8 wherein said electrical means compriseselectrical leads directly connected to release of said elements.

12. The invention of claim 11 wherein said electrical means comprises apair of electrical contacts.

13. The invention of claim 12. wherein one of saidcontacts is connectedto and moves with said bimetallic element.

14. In a method of actuating a tire link to release the link elementsfrom their engaged condition, the improvement comprising: electricallyheating said link to control the engagement of said link elementswithout changing the state of the link.

15. In the method of claim 14 applied to a link having a bimetallicelement to control the engagement of said link elements, the improvementcomprising: remotely supplying electrical current directly to saidbimetallic element to heat said element to control said engagement.

16. The invention of claim 15, wherein said current is continuouslysupplied to said bimetallic element to retain said link elements intheir engaged condition.

17. In the method of claim 15 automatically controlling the currentsupplied in response to the position of the bimetallic element.

18. In the method of claim 14 automatically electrically signalling therelease of said elements.

1. A releasable link having only two elements comprising: a firstelement; and a separate heat activated bimetallic second element notfixedly connected to, but directly engaged with said first element andcoacting therewith to allow said elements to separate in response totemperature change without changing the state of either element.
 2. Theinvention of claim 1 wherein a remotely controlled heating means isconnected to said bimetallic element for actuating said bimetallicelement.
 3. The invention of claim 2 wherein said heating meanscompRises an electric heating element engaging said bimetallic element.4. The invention of claim 1 wherein a pin is attached to said bimetallicelement and passes through said first element.
 5. The invention of claim4 wherein said bimetallic element is fixedly connected to a base at oneend and said pin is connected to the free end thereof.
 6. The inventionof claim 4 wherein said second element includes a means embracing saidfirst element to confine it.
 7. The invention of claim 1 wherein saidsecond element is provided with means to provide an air passage to thebimetal.
 8. The invention of claim 1 wherein said electrical means areconnected to said bimetallic element for heating said element.
 9. Theinvention of claim 8 wherein said electrical means comprises electricalleads directly connected to said bimetallic element.
 10. The inventionof claim 8 wherein said electrical means comprise heating means and apair of electrical contacts attached to said link, one of said contactsbeing connected to said bimetallic element, whereby as said bimetallicelement moves in response to heat, said contact moves with it.
 11. Theinvention of claim 1 wherein electrical means are provided attached tosaid link to signal the release of said elements.
 12. The invention ofclaim 11 wherein said electrical means comprises a pair of electricalcontacts.
 13. The invention of claim 12 wherein one of said contacts isconnected to and moves with said bimetallic element.
 14. In a method ofactuating a fire link to release the link elements from their engagedcondition, the improvement comprising: electrically heating said link tocontrol the engagement of said link elements without changing the stateof the link.
 15. In the method of claim 14 applied to a link having abimetallic element to control the engagement of said link elements, theimprovement comprising: remotely supplying electrical current directlyto said bimetallic element to heat said element to control saidengagement.
 16. The invention of claim 15, wherein said current iscontinuously supplied to said bimetallic element to retain said linkelements in their engaged condition.
 17. In the method of claim 15automatically controlling the current supplied in response to theposition of the bimetallic element.
 18. In the method of claim 14automatically electrically signalling the release of said elements.